Combination sagger and setter for bisque firing vitrified china



Dec. 29, 19.42. J. RQGEDNETZ COMBINATION SAGGER AND SETTERFOR BISQUE FIRING VITRIFIEDQHINA Filed uor. 20, 1940 I l I I l I I I 1 I I I 1 l I I Patented Dec. 29, 11942 COMBINATION SAGGER SETTER 'FOR, BISQUE FIRING VITRIFVIED CHINA John B. Gednetz, Glendale, Calif., assignor to Gladding, McBean & 00., Los Angeles, CaliL, a corporation of California Application November 20, 1940, S erial.No. 366,429

14 Claims.

My invention relates to the manufacture of vitrified china bisque. In the manufacture of this type of china it has been difiicult to produce plates having the so-called flat rims, that is, rims with but little upcurve. In the prior practice there has been a great loss due to the unevenshrinlb;

ing of the plates and uneven support by the setter which caused a distortion or warping of the plates. For instance, one cause ofthe warping is due to the plate sticking more or less on one side of the setter and the contraction causing the other side to move inwardly on the setter to a greater extent than desired. Thus as the plate is .unevenly supported in the setter when subject to the firing heat, it sags to conform to the shape of the supports.

My invention of the combined sagger and setter of the particular design eliminates entirely the use of silica powder or'sand on which the'plates may be bedded to form a bung, that is, a stack 5 of the plates usually 8 to 16 high and enclosed by the sagger. Such amanner of firing bisque china results in a considerable wastage through nonuniformity of product, warping, etc. Also in this former practice silica or sand dust is a decided hazard to the operators, it being difficult to prevent silicosis.

, I designate my invention as a combination sagger and setter in that the upper or obverse surface forms an individual setter for each plate and the outer flange together with the ledge for stacking develops an enclosing sagger. The combined structures thus when built up form a bung 0r stack of the desired number of plates, each supported on its own combined saggerand setter.

An object and feature of my invention is the construction of a sagger and setter which will have a center support for the well of the plate when this drops under the influence of the heat, this center support having a peripheral shoulder which engages the foot at the margin of the well of the plate. Therefore in the contraction during firing the foot becomes caught by the shoulder causing centering of the plate developing an even contour necessitated by the shape of the setter. Another feature of my invention is in the type of rim support for the rim of the plate at the peripheral portion of the setter, this being so shaped on its upper surface that as the plate contracts, the rim of the plate sags downwardly and becomes of a shape complementary to the rim support of the setter, this giving an even shape to the rim when the foot is properly centered by engaging the shoulder at the center support for the Well of the plate. I

Another feature of my invention is providing an annular groove or depression at the periphery of.

the rim support. This is so shaped that it provides'a clearance for thefingers of the operator in placing the unburnt plate on the setter. construction also permits the operator to'properly center the unburnt plate on the setter so that it will have the uniform contraction towards the center and thus cause the peripheral edge of the platerim to ride inwardly on the rim support. Other features of my invention comprehend providing an annular space between the shoulder of the setter surrounding the center support and the rim support, this being to accommodate the foot of the unburnt plate and to allow movement of such foot in the firing. The foot of the plate settles downwardly as well as pulls inwardly but at no time touches the bottom of this annular depression. This construction causes the bowl of the plate to acquire the shape as designed and to maintain substantially a similar contour in the finished plate as in the unburnt platewith but slight change due to the shrinkage.

Another detail feature of my invention is that when the unburnt plate is'properly centered it is supported entirely by the outer edge portion of the rim support of the setteri This positions the well of the plate above the center support of the setter and locates the foot of the plate in the annular recess surrounding the shoulder of the center support. The construction of the setter also provides a notch on the upper portion of a depending flange so that the setters may be stacked one above the other, there being sufiicient clearance that an upper setter can in no wise touch the platoon the setter next below.

My invention also comprehends the method of bisque firing in the provision for centering the article by the foot of the plate and therefore causing an even settling downwardly of the rim -as'well as the well of the plate in a" concentric manner. My combined sagger and setter may be made by casting in plaster-molds, or it can be made by dry pressing, or wet pressing in mechanical presses with steel dies. Furthermore, should any warpage or distortion of the combined sagger and setter take place during the drying, or firing, it is possible to economically grind the supporting surfaces, such as the rim and the base to a true surface, in order that the vitrified ware fired on thesetter may be formed in a-true and accurate I shape.

My invention is illustrated in connection with the accompanying drawing, in which: Fig.1 isa side elevationbroken away showing Such part of a stack of combined saggers and setters illustrating a half section with an unburnt plate on the upper and a finished plate in the lower setter.

Fig. 2 is a plan of the sagger and setter of Fig. 1 having a shape to make a conventional square plate.

In the construction illustrating the sagger and setter it is of course made in the proper peripheral shape for the shape of the plate to be fired therein. The sagger and setter designated by the numeral H has a flange l2, this having a slight upward taper. A peripheral ledge |3is used for supporting the sagger and setter next above. Above this and extending inwardly. there is an annular groove or depression 14 to accommodate the fingers of the operator placing the plate. The rim support 15 has an upper surface l6-witha slight concave curve considered in radialdirection, this being to support the rim of the plate. The center portion of th setter .-has a centering support 11 with a peripheralshoulder I-8 extending downwardly therefrom. The upper surface of the center is preferably flat to make a thin fiat bottom plate. An annular recess i9 is formed between the shoulder l8 and the inner edge of the rim support. This is illustrated as having a straight downward slope 20 and a horizontal bot-, tom 2! leading to the shoulder it. This shoulder is slightly tapered upwardly. The material of the sagger and setter is made substantially of uniform thickness which develops a somewhat deep annular space 25 below the rim support 15, the clearance space orgroove l4 and there is a central space 26 inside of the shoulder l8. On account of there being a rather deep annular recess l9 there is the annular depressedsectionzl, however it will be noted that no point of the-sa ger and setter can contact the plate next below in any stages of the operation. l v

In order to identify th function of the various portions, an unfinishedplate is indicated by the numeral til. This has a well 3! an annularfoot 32, an upwardly curved bowl portion-33 and the rim 3d. The peripheral rim-edge;35, it will be noted, projectsbeyond the outer edge of the rim support, that is, beyond the surf-ace l5 extending well over the groove M. This allows theoperator to place the plate by gripping-the edge :withv the finger tips and accurately centering the plate in reference to the rim support and the sagger as a whole. As is well known in the art, there is a quite decided contraction and shrinkage inbisque firing of vitrified china so that although the edge 35 projects well beyond any supporting surface, r."

the contraction of the plate pulls this inwardly.

It will be noted that the rim 34 of the plate is supported and contacts the setter at the outer edge of the surface lb of the rim support so that the inner portion of the plate rim is entirely unsupported and the outer portion towards the edge 35 is also unsupported. The well 3! of the plate. is also positioned above the well support l1, however this plate is accurately centered with the foot above the annular recess i9 and spaced well from the annular shoulder it of the centersupport. The distance across the setter from'the shoulder I8 is always slightly less than any possible distance between the foot 32 when the platehas contracted the maximum amount, therefore in the contraction in firing at least one portion of the foot 32 will engage a portion of the shoulder 18. This causes an accurate centeringof the plate as the well portion sinks downwardly and rests on the center support I1 and also causes the rim 34 of the plate to pull it evenly on the rim support I5. The plate rim settles downwardly so that there is a complete annular surface support on the rim support of the setter.

. There is however no direct support for the bowl the same uniformity as they contract to the final ,measurement as indicated by the lowermost plate in Fig. 1.

It will be noted by the above description that substantially the same design of the setter is suitable for round plates, the construction illustrated in Fig. 1 showing in section substantially a diameter line. This type is suitable for a plate which has quite a pronounced concave portion in the ball of such plate. It will be noted that the setter at the. flange i2 is somewhat tapered so that when these are stacked the operator may engage the lower edge of each flange in placing this in a stack or removing the same.

My invention, also it will be noted, vincludes an improvement in the method of bisque firing vitrifled china in that I control the concentric shrinking and downward settling of articles such as the plate. For instance I have provision for setting the unfired article with the rim edge'projectin beyond the rim support of the sagger. Then on firing as the well of the plate and the foot settles downwardly, I positively stop the shrinkage laterally by the portion of the foot which-first engages the rim surrounding the well support of the sagger and setter, hence the remaining portion of the foot is brought into substantially concentric relation to the shoulder and-an even support given to the well of the plate. This centering action causes the rim as it shrinks and settles downwardly to be drawn inwardly evenly and con-centric with the center of the plate, the rim conforming to the obversesurface of the rim support of the setter. t will thus be seenthat the obverse side of the setter as to the wellsupport and the rim support gives adequate support and shaping to the reverse side of the plate in regard to the well and a portion of the rim, hence as the unfired plate is made of the desired thickness to have the proper contraction, the finished plate is therefore governed as to its shape by the contact surfaces on the obverse side ofthe sagger and setter.

Various changes may be made in the details of the construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

l. A combination sagger and setter having a peripheral support for the rim of afooted plate with a grooved portion'for the operator to center the plate and to accommodate his fingers, the sagger having a center portion with a shoulder to engage the foot of a plate on shrinking and thus retain the plate on complete shrinking centered as to the sagger and setter.

2. In a device as described, a sagger and setter having a peripheral somewhat flattened rim support portion with an annular downwardly extending groove to accommodate the fingers-oi the operator setting a footedplate with the rim of the plate to rest on the rim support of the sagger, the sagger having a central portion with a peripheral shoulder to engage the foot of a plate on shrinking of such foot and thus form the centering support for the plate.

3. A combination sagger and setter for bisque firing vitrified footed china having an annular rim support shaped to conform to the reverse side of the rim of the china article, a center support substantially the shape on its obverse, surface of the reverse side of the well of the article and having a shoulder to engage the depending foot of the china article, the rim support being adapted to form the entire support for the unfired article with the rim of the article engaging the outer portion of the rim support and the main portion of the rim of the article positioned above the upper surface of the rim support, the article on firing being adapted to settle downwardly and to shrink inwardly with the foot engaging the said shoulder and thereby centering the article, the well of the articles contacting the well support and the rim of the article conforming on its reverse side to the shape of the rim support.

4. A combination sagger and setter for bisque firing vitrified footed china having an annular rim support shaped to conform to the reverse side of the rim of the china article, a center support substantially the shape on its obverse surface of the reverseside of the well of the article and having a shoulder to engage the depending foot of the china article, the rim support being adapted to form the entire support for the.

unfired article with the rim of the article engaging the outer portion of the rim supportand the main portion of the rim of the article positioned above the upper surface of the rim support, the article on firing being adapted to settle downwardly and to shrink inwardly with the foot engaging the said shoulder and thereby centering the article, the well of the article contacting the well support and the rim of the article conforming on its reverse side to the shape of the rim support, an annular groove positioned outside of the rim support and giving the clearance space for the fingers of an operator placing the article on the combination setter and sagger.

5. In a combination setter and sagger for firing footed china articles having an annular rim support, a central well support and a shoulder, the said shoulder being adapted to engage the foot of a china article on shrinkage and settling with the well of the article supported by the well support and the rim of the article conforming on its reverse side to the obverse shape of the rim support.

6. In a combination setter and sagger for firing footed china articles having an annular rim support, a central well support and a shoulder, the said shoulder being adapted to engage the foot of a china article on shrinking and settling with the well of the article supported by the well support and the rim of the article conforming on its reverse side to the obverse shape of the rim 65 support, an annular groove positioned beyond the periphery of the rim support providing a means on its obverse face to form supports for the reverse side of an unfired and a fired "china article, there being a peripheral groove to accommodate the fingers of an operator when setting and centering an unfired article, a supporting surface on the outside of the said groove adapted to engage and support a sagger next above. v

9. A combination sagger and setter having surfaces on its observe side to support an unfired article and to engage a plurality of surfaces on the reverseof the fired article after shrinking and settling, there being a peripheral flange on the sagger and setter having a stacking surface on its upper portion for stacking the saggers and setters one above the other, each sagger and setter having a groove positioned inwardly of the said stacking surface to accommodate the fingers of an operator when setting an unfired article on the observe surface of the setter and sagger.

10. In the method of bisque firing vitrified china comprising supporting an unfired article by the reverse side of its rim, causing the article to shrink in diameter and to settle downwardly when fired, restraining the inward movement of part of the article when shrinking and thereby cause the While article to shrink and settle downwardly concentric with its center.

11. In the method of bisque firing vitrified footed china comprising centering as unfired plate-like article with the rim of the plate extending beyond a rim support of a mgger and setter, on firing causing the plate-like article to contract in diameter and to settle downwardly, bringing at least a portion of the foot of the article. at one side in engagement with a centering stop and hence causing the article to contract uniformly as to its center and to settle downwardly uniformly as to its center thereby forming a rim of uniform depth relative to the well of the article.

12. A combination sagger and setter having an annular supporting surface adapted to support the rim of a footed article to be fired, and an upright annular shoulder disposed below and within said surface arranged to be engaged by the foot of the article during contraction of the article while it is being fired so as to center the article during firing and contraction with relation to the sagger and setter. p

13. A combination sagger and setter having an annular supporting surface adapted to support space for the fingers of an operator to center an unfired article.

7. A combination sagger and setter having means on its obverse face to form supports for the reverse side of an unfired and a fired china article, there being a peripheral groove to accommodate the fingers of an operator When'setting and centering an unfired article.

8. A combination sagger and setter having the rim of a. footed article to be fired, and an upright annular shoulder disposed below and within said surface arranged to be engaged by the foot of the article during contraction of the article while it is being fired so as to center the article during firing and contraction with relation to the sagger and setter, said sagger and setter being relieved outwardly of said supporting surface to provide a finger-receiving space in positioning an article to be fired thereon.

14. A combination sagger and setter having an annular supporting surface adapted to support the rim of a footed article to be fired, and a central supporting surface designed to support the center of the article, said central supporting surface terminating at its edges in an upright shoulder engageable by the foot of the article on contraction during firing so as to center the article with relation to the sagger and setter.

J OHN. R. GEDNETZ. 

